Conventionally, as this type of steering wheel planar heat generating element for automotive vehicles or motorboats, there have been many planar heat generating elements in which a heating heater which generates heat by being connected to a power supply is held in place between a substrate of a steering wheel and a covering material which is provided with a sheet, synthetic resin, fabric product or, in particular, leather (for example, refer to Patent Document No. 1).
FIG. 6 shows a conventional steering wheel and FIG. 7 shows a plan view of a conventional steering wheel planar heat generating element. As is shown in FIGS. 6 and 7, 1 denotes a planar heat generating element, 2 a heater which is provided with a warp knitted fabric which can be elongated, 3 a woven fabric of textile fibers which fringes the heater along a joint edge portion, and 4 a connecting line which extends over the overall width of the warp knitted fabric 2 to connect a power supply with the heater 2, and the planar heat generating element 1 is bonded to a covering material 5 for a steering wheel. The planar heat generating element 1 bonded to the covering material 5 is then attached to a steering wheel provided with a ring portion and spoke portions for use.
Patent Document No. 1: JP-A-4-15162